imports: import shutil
  import tempfile
  import unittest
  from transformers import SPIECE_UNDERLINE, BatchEncoding, MBart50Tokenizer, MBart50TokenizerFast, is_torch_available
  from transformers.testing_utils import get_tests_dir, nested_simplify, require_sentencepiece, require_tokenizers, require_torch, slow
  from ...test_tokenization_common import TokenizerTesterMixin
label_desc: Use image node_id 6 for calling the MBart50TokenizationTest obj's underlying member method code with example usage: obj.test_tokenizer_integration() without return types